1. Filed of the Invention
The present invention relates to a flat display apparatus.
2. Description of the Related Art
Recently, various flat display apparatuses using a plate-like thin display panel such as a plasma display panel (hereinafter, abbreviated to PDP), a liquid crystal display panel, or an organic electroluminescence display panel are being developed.
FIG. 1 shows an example of the whole configuration of a plasma display apparatus in which such a PDP is incorporated.
As shown in the figure, a case which houses a PDP 1 is configured by a front face frame 6 in which a front face cover made of glass or the like is placed in an opening, and a rear cover 7 made of a metal.
The PDP 1 is bonded via a heat conductive sheet 8 to a front face of a chassis member 3 made of an aluminum alloy or the like, to be held thereby. A plurality of circuit blocks (circuit boards) 2 such as a scanning circuit board on which a driving circuit for driving the displaying operation of the PDP 1, and a driving circuit board on which a power supply circuit for supplying an electric power to the driving circuit are attached to the rear face of the chassis member 3.
The heat conductive sheet 8 efficiently conducts heat generated by the PDP 1 to the chassis member 3 so that the heat is radiated therefrom. The chassis member 3 is requested to perform a function of serving as a holding member for holding the PDP 1, and also a further function of radiating the heat generated by the PDP 1 to cool the PDP 1.
FIGS. 2 and 3 show the structure for connecting the PDP 1 with the chassis member 3 in the conventional example of a flat display apparatus.
As shown in the figures, the PDP 1 is configured by bonding a front face glass substrate 1A to a back face glass substrate 1B via a discharge space 1C. The circuit boards 2 for driving the PDP 1 are mounted on the PDP via the chassis member 3.
The chassis member 3 is a plate-like member made of a metal such as an aluminum alloy having a high heat conductivity. The PDP 1 and the circuit boards 2 are electrically connected to each other through a flexible cable 4. As shown in FIG. 3, the chassis member 3 and the PDP 1 are fixed to each other by a plurality of double-sided adhesive tapes 5 which are bonded to the outer face of the back face glass substrate 1B of the PDP 1 (the back face of the PDP 1).
Recently, in order to reduce industrial waste and economize raw material resources, a recycling process of recovering used products, disassembling them, and returning glass and metal parts to resources becomes an important issue in various industrial fields.
In the thus configured flat display apparatus also, therefore, it is contemplated that the display panel formed by a glass substrate, and the chassis member made of a metal such as an aluminum alloy are separated from each other to be recycled.
However, the above-described flat display apparatus has problems. One of the problems is as follows. Usually, the double-sided adhesive tapes 5 which are used for bonding the PDP 1 to the chassis member 3 are formed by stacking adhesive layers of acrylic paste or the like on both surfaces of a tape backing formed by an acrylic film or the like, and exert a high adhesive force. In order to peel off the double-sided adhesive tapes 5, therefore, a special peeling method using a solvent, a heating treatment, or a water pressure is required. This causes a problem in that the cost for recycling is increased.
When a failure occurs in the PDP 1 in a production line or the PDP is to be repaired after shipment, it is difficult to separate the PDP 1 from the chassis member 3, thereby causing another problem in that a work of replacing a faulty component cannot be easily conducted.
Therefore, a countermeasure has been considered in which plural double-sided adhesive tapes are applied with forming large application intervals so as to reduce the region (area) where actual bonding is performed, thereby saving the trouble of peeling off the double-sided adhesive tapes. In the countermeasure, in a region where the double-sided adhesive tapes are not applied, a gap is formed between a display panel and a chassis member, thereby causing a problem in that the formation of the gap reduces the amount of heat conduction from the display panel to the chassis member. Moreover, a temperature difference is produced between the applied portion where the display panel and the chassis member are in contact with each other via the double-sided adhesive tapes, and the non-applied portion where the double-sided adhesive tapes do not exist and the gap is formed, thereby causing thermal stress and strain in the display panel. This may adversely affect the display characteristics.
In order to solve the problems, a configuration has been proposed in which a material having an excellent shrink property is used as tape backings of double-sided adhesive tapes for bonding and fixing the back face of a display panel to a chassis member, and the adhesive forces of adhesive layers to be stacked on both surfaces of each tape backing are weakened. In this configuration, when a tension of a given level or higher in the longitudinal direction is applied to ends of the applied double-sided adhesive tapes, the tapes can be easily peeled off (for example, see JP-A-2002-268577).
In this case, while a necessary area is ensured between the display panel and the chassis member, the peeling work is facilitated, and the disassembling work for recycling, and the work of replacing components can be easily conducted.
In the double-sided adhesive tape disclosed in JP-A-2002-268577, a polymer foam layer or a polymer film layer is used as the tape backing to ensure a breaking elongation of 300% or more. Since the polymer foam layer or the polymer film layer is made of an acrylic polymer, polyurethane, or a combination of these materials, the layer is highly thermally insulative. Therefore, there is a problem in that it is difficult to rapidly conduct heat generated by the display panel to the chassis member.
The double-sided adhesive tape disclosed in JP-A-2002-268577, and the conventional double-sided adhesive tape 5 in which an acrylic film is used as the tape backing have another problem as follows. In the case where the tape is densely laid to ensure a large adhesive surface, the connection state between the PDP 1 and the chassis member 3 due to adhesion becomes rigid and stiff. When an external impact force is applied to the chassis member 3 during transportation or the like, therefore, the impact force is directly transmitted to the display panel via the adhesive layer of the double-sided adhesive tape, thereby causing the possibility that the display panel is broken.